This Center Grant proposal seeks partial funding for the core activities of the Population Studies Center. The funding requested covers: 1) pure administrative costs for the program as a whole, 2) partial cost associated with PSC generalized computer programming, data archives maintenance and data processing, independent of the sponsored research carried out at the Center, 3) costs for general library needs at PSC, 4) partial costs for site expansion. The major research activities at PSC include: comparative fertility and family planning studies, the measurement and implications of popuulation clustering, women's roles and fertility, the scaling of family size preferences, demographic characteristics and socioeconomic attainment, economic research on human resource development, stochastic models for the analysis of demographic time series, the distribution and differentiation of population within metropolitan areas, the assessment and effects of measurement error in demographic data, college enrollment and policies affecting college enrollment, historical demographic studies, diet and multiple sclerosis (detailed descriptions of the research are contained in Description of the Research Program).